Process of preserving wood.



Specification of Letters Patent.

Patented Sept. 22, 1908.

Application filed march 18, 1908. Serial No. 421,806.

1 To all whom it may concern:

. solution. The woodis uniformly throughout 'is subjects Be it knownthat I, CHARLES HOWARD, a citizen of the United States, residing at NewYork, in the county of New York and State ofNew York, have inventedcertain new and useful Improvements in Processes of Preserving Wood, ofwhich the following is a specification.

My invention relates to an improved process-of preserving wood, and itconsists-in the steps and processes herein described and claimed. Anobject of my invention is to provide an improved process whereby aneflicient pres: ervation of the wood fibers will be obtained a mass ofany size. A further object of my invention is to prov1 de an improvedprocess adapted to operate wit a minimum of expense and timeforpreserving wood of any sizeand character, without danger of injuring thewood fibers or of subsequent-deterioration thereof.

n the operationbf my invention, the wood d to heat for a sufficient timeto evaporate any water which ma have been absorbed bythe wood, and alsothe relatively volatile aqueous constituents thereof. The heated wood isthen treated with acool aqueous solution of magnesium sulfate having astrength of from 2% to 20%, according to the character of the wood.During this ste the a ueous vapor entangled among t e wood bers as aresult of the previous heating will be condensed. by the cool solution;thereby producing a partial vacuum in the interstices of the wood andcausing a rapid and thorough permeation of the wood by the thensubjected to heat for expelling the excess moisture, and treated wit aheated aqueous solution of barium chlorid having a strength offrom 1 Thesolution is then drawn oif, and the aqueous portion of the warm solutionthen evaporated.

' Ar -important advantage of my invention is the thorough and uniformdeposition of the barium chlorid rendered ossible by evaporating themoisture from tl ie wood preliminary to treating it with a heatedaqueous solution of barium chlorid. In carrying out these steps, theslight solubility of magnesium sulfate in a heated aqueous solutionrevents removal of said compound from t e wood wood, and al ment.

chlorid, fills, the pores of the throughout the,mass of the preservingprocesses,

- fibers during'treatment with the heated solution of barium chlorid.All danger of so removing the magnesium sulfate, or of causing an irrelar distribution thereof through the heated barium wood, y the actionof'the thereby insurchlorid solution is obviated; ing a uniformity ofcondition so preventing deterioration of the excess amount of bariumchlorid solution which is necessarily employed in the treat- By myimproved process, the magnesium sulfate 1s transforme I to magnesiumchlorid,

h becomes fixed or united with the albuminous constituents of the woodand constitutes an efficient preservative; the barium chlorid beingtransformed to barium sulfate, which; intermixed with the magnesium wooduniformly latter. My invention provides, therefore, means for obtaininga regular distribution of. the preservative agent and a uniform filllngof the ores of the wood throughout the mass of the atter by theinsoluble barlum sulfate. This obviates the defects found inexistingwood in which the interior portions of the wood becomedeteriorated and rotted by the absorption and retent on of wateradmitted thereto by cracks or spike holes in the-wood.

I have described a preferred and satisfactory method of carrying out 111invention, but obviously changes could e made within the spirit andscope of the invention.

Having thus described my I claim as. new and desire to secure byLetters-Patent is:

1. The herein described serving wood, which consists in drying the woodtreating the dried wood with a cool a ue s solution of magnesiumsulfate, 'expe ling'excess moisture fromthe wood, and treating the woodwith a hot aqueous solution of barium chlorid;

2. The herein described process of preserving wood, which consists insubjecting the wood. to heat, treating the heated woo with 8..0001aqueous solution of magnesium sulfate, heating the wood to expel excessmoisture, and treating the heated wood with ahot aqueous solution ofbarium chlorid.

3 Theherein described process of prethroughout the invention, wh'atprocess of pre- I serving Wood, which consists in subjecting intestimony whereof I affix my signature the wood to heat, treating theheatecl wood 1n presence of two witnesses.

with a cool aqueous solution containing below 20% of magnesium sulfate,heating the CHARLES HOWARD 5 Wood to expel excess moisture, and treatingWitnesses:

the heated wood with a hot aqueous solution G. AYRES,-

containing below 6 7; of barium chlorid. H. G. ROBINETTE.

